Pharyngula

Jurassic beaver

Say hello to Castorocauda lutrasimilis, a primitive mammalioform from the middle Jurassic—164 million years ago. Despite its great age, it has evidence of fur and guard hairs still preserved in the fossil, and was rather large for its time. It’s estimated to have weighed about 500g (about a pound) and was over 400mm (over a foot) long in life, and as you can see from the reconstruction, shows signs of being aquatic. In size and lifestyle, it probably resembled the modern platypus.

i-116c078dc64aa893f63c7f28f7c662fb-castorocauda.jpg

i-3ee0115b5f55970b164534333a795964-castorocauda_fossil.jpg
Holotype of Castorocauda lutrasimilis [Jinzhou Museum of Paleontology (JZMP) 04-117]. (A) Photograph of the holotype. (B) Osteological structures and preserved soft-tissue features. Abbreviations: as, astragalus; ca, caudal vertebrae; cn, ento-, meso-, and ecto-cuneiforms; co, coronoid process of dentary; cp, carpals; cs, calcaneus; ec, ectepicondyle and supinator shelf (humerus); ef, entepicondyle foramen; ep?, probable epipubis; is, ischium; J, jugal; L1-6, lumbar ribs 1 to 6; m, molars; mb, manubrium of malleus; mp, metacarpals; mx, maxilla; px, premaxilla; ra, radius; rc, radial condyle; S1-2, sacrals 1 and 2; sp, extratarsal (“poisonous”) spur; t4-t14 (preserved ribs through thoracic 17); uc, ulnar condyle; ul, ulna.

Ji Q, Luo Z-X, Yuan C-X, Tabrum AR (2006) A Swimming Mammaliaform from the Middle Jurassic and Ecomorphological Diversification of Early Mammals. Science 311(5764):1123-1127.


Since people were asking about the phylogenetic relationships of this animal to modern forms, here’s a cladogram. The modern platypus is Ornithorhynchus, about the middle of the list; Didelphis is the opossum.

i-3258630384ea4b54d4d6ddda2b82a91f-mammaliform_phylo.jpg

Comments

  1. #1 dbpitt
    February 23, 2006

    Wow. It does have a resemblance to a platypus. Was it a monotreme?

  2. #2 Observer
    February 23, 2006

    How long before the first creation scientist puts out a press release saying this discovery is some kind of “fatal blow” to the theory of evolution? I put the over/under at 24 hours. Bonus points if the creationist fails to mention the implications of this discovery on creationist theory or ignores the “164 million years old” number.

  3. #3 pough
    February 23, 2006

    Other descriptions I’ve read say beaver/otter, but isn’t it more likely to be a monotreme like a platypus? It looks to me like platypus/otter would be a better description. Especially with those “poisonous” spurs!

  4. #4 PZ Myers
    February 23, 2006

    It’s no more a platypus than it is a beaver, of course — it’s remote from both. I think the name Castorocauda (“beaver tail”) indicates what the finder is thinking, though.

    Besides, “Jurassic Beaver” sounds like a great title for a porn movie.

  5. #5 pough
    February 23, 2006

    That would make a great porno movie title, but whether or not this thing is a monotreme makes a big difference. Only one hole means no real beaver pun AND reduces the potential kink factor!

  6. #6 Bruce
    February 23, 2006

    It would be a great title for a porn movie.
    There seems to be more and more finds coming from China. Is there a political/sciency reason for this? I never heard about them digging stuff when I was younger.

  7. #7 plunge
    February 23, 2006

    Well, China wasn’t really a great place for science during the cultural revolution and so forth: they may not be democratic now, but they are a much more mainstream part of the scientific community than they were back when intellectuals were being forced a gunpoint to farm instead of do biology. China does, however, have a lot of great geologic features that make it particularly rich in terms of new places to explore for fossils.

  8. #8 Gerardo Camilo
    February 23, 2006

    Nice beaver;)

  9. #9 Mark
    February 23, 2006

    “How long before the first creation scientist puts out a press release saying this discovery is some kind of “fatal blow” to the theory of evolution?”

    Try http://www.creationtours.com/

    I found this site from Pharygula earlier this week.

  10. #10 Observer
    February 23, 2006

    Wow, Mark, a double-whammy! Not only is it a “big setback” for evolutionists but creationtours also ignores the age of the fossil!

    Maybe I should’ve been an Engineer instead of an Astronomer. I could write that stuff.

  11. #11 Torbjorn Larsson
    February 23, 2006

    “”Jurassic Beaver” sounds like a great title for a porn movie.”

    Since the play field opened; this confirms my suspicion that old beavers may be nice too.

  12. #12 Torbjorn Larsson
    February 23, 2006

    Oh, and just so I’m not misunderstood: I expect I will have to find out eventually. But PZ have now put my fears to rest. 🙂

  13. #13 Sir Unimaginative
    February 23, 2006

    Creation Tours. *Hee.*

    How do I discuss this…. Oh yes.

    Creationism is like looking at a bird behaving in a way that your birdwatcher’s guide says it cannot do, then saying that the bird is wrong.

    In any case: I look forward to more news on this. That is one old – and big – mammaloid.

  14. #14 Western Geologist
    February 23, 2006

    “How long before the first creation scientist puts out a press release saying this discovery is some kind of “fatal blow” to the theory of evolution?”

    Try this guy:

    http://www.mikejanitch.com/blog/_archives/2006/2/23/1780413.html

    It’s hard to pick just one favorite quote from that link, but I’m leaning toward this:

    “Once again, science proved completely wrong, mammals existed far earlier, and were far more complex than the “theory of evolution” should allow, as mammals (according to science and the theory) were only tiny little creatures in the ground, not swimming fully haired beavers.”

  15. #15 Virge
    February 24, 2006

    One-sixty million years ago,
    We see from prints, and tooth and bone,
    The oldest furry mammal known
    Would dive for piscine treats below…

    Furry Fossil

  16. #16 Jaime Headden
    February 24, 2006

    A creationist claiming this is a blow to evolution is unlikely. They are more likely, as one tried on Panda’s Thumb, to simply claim it’s fake and cackle at our self-delusionment.

    Anyways, the beds have been dated by 2004-2005 studies, one based on volcanic tuffs, as Lower Cretaceous, probably Berriasian through Hauterivian. The beds may be the same age as the Lower Cretaceous Yixian Formation which has similarly produced other fantastic mammals such as the giant Repenomamus and the almost Rosetta Stone-like Zhangheotherium.

  17. #17 robopox
    February 24, 2006

    This fossil may be a gold mine for infectious disease specialists.
    Obviously, it could be the initial host for myriad mammalian disesases;
    Rocky Mountain Spotted Beaver, Rheumatic Beaver, Scarlet Beaver,
    Typhoid Beaver, and the dreaded Yellow Beaver.
    I assume Aetiology will have a clean dissection of the
    implications shortly.
    Will Oral Flora be starring in Jurassic Beaver?
    I loved her in Clan of the Cave Beaver…..

  18. #18 osteopath
    February 24, 2006

    “This directly contradicts evolutionists beliefs that mammals were too timid to eat dinosaurs.”

    HA! I have never seen any reference to any claims that makes the sweeping generalization that mammals were too timid to eat dinosaurs. This statement shows that creationists have no clue whatsoever what evolutionists say about not only dinosaurs but predator/ prey relationships, animal behavior or logic.

    I would love to see his references or any peer reviewed journal to see where he picked up this claim.

  19. #19 Melanie Reap
    February 24, 2006

    I’m so glad to kow that I wasn’t the only one to read something naughty into the title. Say no more, nudge, nudge.

  20. #20 BronzeDog
    February 24, 2006

    Creationism is like looking at a bird behaving in a way that your birdwatcher’s guide says it cannot do, then saying that the bird is wrong.

    Another theft-worthy quote.

  21. #21 Vince Sherwin
    February 24, 2006

    I always thought that the notion that the all mammals in the Mesozoic were no larger than a shrew didn’t seem right. I’m no biologist (more of a biology “fan”)so it was just based on my gut feeling as to how life operates and evolves. It’s sort of like how I feel about the “bug net” theory of how bird wings evolved. It seems stupid but I don’t have the technical skills to fully explain why…it’s just based on my observations of how life operates today. I would expect there would be Mesozioc ecological niches available for warm-blooded quadrupeds that are bigger than a mouse yet smaller than the smallest quadrupedal dinosaurs.

  22. #22 Carel
    February 24, 2006

    Castorocauda was a docodont, an early mammal group that diverged and died out before the appearance of any modern mammal orders, including monotremes. The morphological similarities with beavers and platypuses is pure convergence. I’m still working on a way to use “docodont” into a porn title.

  23. #23 mark
    February 24, 2006

    Docodont Evil? Sorry, not much to work with.

  24. #24 Memo
    February 24, 2006

    “…were only tiny little creatures in the ground, not swimming fully haired beavers.”

    yeah, shaving was the fashion before the chixculub impact.

  25. #25 Mike
    February 26, 2006

    I suppose I should attempt to defend myself in this commentary… I am claiming that yes indeed this is a “blow” to the current “origin of species”.

    If mammals were far more complex far earlier than previously theorized, then the whole scheme put forth by Darwinian evolution… simple cell on upwards, is pushed back much further, into the Triassic.

    Basically the whole point of my posting was to show the OBVIOUS conflict here… that there either there is a timeline contradiction in regards to climate and geology, or a false theory as to how/when life evolved.

    And despite all the name calling, and inference of being a fundamentalist christian by the guy who posted this… the fact still remaains that 4 days ago, If I asked the people in this room if complex mammals existed in the Triassic, you would have said no. Now you will say yes.

    But if I went to a textbook, or to the local college or highschool, they would still tell me that we evolved from little mammals in the ground from post triassic. Don’t you see that if a mammal was far more complex far earlier, that it throws the whole freakin’ timeline chart that evolution is based upon out the window?

    You don’t have to be a christian ID proponent to see that. Just have to be willing to admit you were wrong. And as we all know, science is NEVER wrong .. hehe

  26. #26 PZ Myers
    February 26, 2006

    the fact still remaains that 4 days ago, If I asked the people in this room if complex mammals existed in the Triassic, you would have said no. Now you will say yes.

    Absolutely false, and a complete misinterpretation of this discovery.

    This is a primitive mammal. It has features that are clearly ancestral. If you’d asked if we thought there were eutherian mammals in the Triassic, we would have said no, sure…but this is not a eutherian. We also know about mammal-like reptiles from the Permian (before the Triassic, in case you didn’t know), and certainly would not try to claim that our lineage arose in the Triassic.

    You are flinging around the word “complex” as if it has some special significance in this situation, and are clearly eliding its meaning to suggest untenable interpretations unsupported by the evidence.

    If you get called names for this, keep in mind that you are the one flaunting your ignorance in a fallacious attempt to represent your faith. Your fellow Christians are the ones who ought to be most upset with you. Testify, brother–you’re doing a fine job of validating my opinion of Christianity.

  27. #27 mike
    February 27, 2006

    Christian? who said anything about religion? Funny that you think things are as black and white as that, and that I can be classified like one of your false species.

    I laugh at the example of a hybrid reptile-mammal, its humorous, and yes has already been disproved, or actually proved fraudulent… much like the spottted moths, and Haeckles embryos… if you think about the number of fraudulent “experiments” that have been done in the name of Darwin in order to prove it correct.

    What are you people going to do when you find a skeleton of a mammal in a layer of Permain rock? Are you going to then push back evolution another Era? Are you going to call others like me names and no even look objectively at your stance?

    If evolution was real, museums wouldn’t have foam rubber sculptures of ficticious ape men, and you would have 50,000 different animal skeleton “missing Links” for every species to ever existed in the world. As the mouse would have to have formed a skeleton when it grew beaver flippers, when it grew new hair structures… there would be 20 different versions of Jurassic beaver over the course of history, and you would have found subsequent remains of “future revisions” of Jurassic Beaver.

    Not to mention you would be able to site 1,000,000 different fossil examples of plants that have gone from being one kind of plant to another… you’d be able to show me the sugar cane that was half grape vine. Or the sycamore that putt off oak leaves.

    yes, i realize the plant expectation is absurd, just as the animal expetation is. No one would expect a Pine tree to grow roots like Marijuana… why would you expect a mouse to grow flippers?

    Oh wait, thats right.. there is no fossil evidence… only skeletons of animals that already existed, and there are NO skeletons of animals in the process of chaning from a rodent to Jurassic beaver.. all this is now supposed to have taken place in the Permian?

    Even though modern science (up until a few days ago) said this was impossible due to the climate on the earth in PRE-Permian days? Or are you going to re-write that theory too?

  28. #28 Jeffery Keown
    February 27, 2006

    I brought Mike over here! I’m SPECIAL!

    Sure, I called him a lotta names, but go read that rash of shit he wrote… you’ll think of a few more!

  29. #29 PZ Myers
    February 27, 2006

    I think Mike is the “special” one.

  30. #30 mike
    February 27, 2006

    just like kids on the playground, calling an outsider with different beliefs “special”, I guess you really mean to call me a retard, as that what people who are “special” really are.

    This says alot about your ability to argue a point.

    The losing evolutionist, like keown, and myers, always manager to skirt the issue of NO skeletal evidence, molecular structures, made up-faux foam rubber museum sculptures in place of real fossils… People like Keown, and Myers completely overlook the fradulence— yes indeed you don’t even acknowledge the MADE UP SCIENCE by bedrock scientists like Haeckel..

    Anyone care to comment on those troubling little facts? Or do Myers, and Keown still want to call me names? I argue that maybe their intellect is really memorized and recited as opposed to learned and tested.

  31. #31 Steviepinhead
    February 27, 2006

    Bleh!

    As if PZ had never discussed the moths or Haeckel before…

    Sigh. It makes one long for the days when the maroons at least came with a creamy filling.

  32. #32 Jeffery Keown
    February 27, 2006

    Haeckel’s been done to death. I pointed the Mikester to talkorigins but he compared it to a propaganda site. There may be no hope for him to understand. I don’t mind though, he kept me busy for a few days. I think when you point someone to a site containing facts, and they don’t read them, and they continue to skawk about it, it illustrates a favorite point of mine:

    Some folks have made up their minds and you can’t change them. I predicted this in one of my posts and he’s playing the same tune.

    [sycophant]

    Oh, and thanks a million for comparing me to Dr. Myers, I’ve never seen my name in the same sentence with his, and I did feel a swelling of pride. The man is a giant. no one articulates the wonder of evolutionary biology better than he.

    [/sycophant]

  33. #33 PZ Myers
    February 27, 2006

    Your “troubling little facts” aren’t facts at all. They’re false. There’s lots of skeletal evidence, the molecular evidence for evolution is growing day by day, and museums are full of real fossils; I’ve been in the storage areas of several museums, and it’s amazing how much stuff is packed in there. That museums use casts for display does not mean that the source material does not exist.

    I wouldn’t call you a “retard,” since that’s offensive to innocent people with disabilities. If you want a label, the most appropriate one here is “liar.” “Fool” works, too.

  34. #34 mike
    February 28, 2006

    Now I’m a liar and a fool… all for questioning the story that’s been presented. Isn’t that what the religious bigots called darwin during his time?

    As for the cast molds– thats not what I’m talking about.. I know cast molds are made of all kinds of ancient fossils.

    I’m talking about the real “hybrid” skeletons that prove without a doubt that a squirrel was once a mouse, or the fossil proof that a pine cone was once a prehisotric acorn.

    If there really were a squirrel half mouse skeleton, or a sycamore with oak leaf structure, then museums would have it on display, and you wouldn’t even have to argue your theory, as it would be hands down proved.

    Instead the earth has millions of species, so statistics tells us that there should be exponential “intermediate” skeletons of all the different species, which proves that mutation over time took place. This is NOT the case though. Rather you have new skeletons, like jurassic beaver, which turn up, and just happen to show that mammals must have been around much earlier, and therefore if they did evolve, the evolution process that Darwin based his theory upon was incorrect, and doesn’t add up.

    If you believe in : a prehistoric ooze that somehow assembled DNA and the basic genome, if you believe that protozoa turned into fish, accept that fish turned into lizards, and that lizards turned into mammals, and mammals somehow have turned into humans,ALL WITHOUT ANY LINK FROM ONE TO ANOTHER, then you’re smoking crack.

    Not to mention you would have to explain irreducible complexity. Oh wait you already have explained that.. it was just a big accident, or better yet.. its just rhetoric from liar’s and fools.

    I think Iraq is looking for a new information minister to promote propaganda.. you fit the bill perfectly. you remember the information minister don’t you.. the guy who denied the USA was in baghdad, when on CNN we saw tanks rolling through the streets of the downtown area. The analogy is clear.

    ID is the tank on the street of baghdad that everyone can see is real, and you are the information minister with his made up stories and BS rhetoric.

    And jeff keown is the loyal follower, the freedom fighter, the suicide bomber, who goes onto other peoples blogs (like mine) to crusade for his beliefs. It just so happens that I was able to track jeff keown to this site. Thus brininging me to the “terroist training camp”. heheh

  35. #35 mike
    February 28, 2006

    Also, Myers says this in another of his articles..
    “My point is that you don’t have to be an expert in the discipline to find evidence that Skell is completely wrong; all it takes is a casual perusal of the general scientific literature and a prepared mind”

    I suppose you don’t apply this rule to everyone, just yourself, and just when it applies to ID proponents right? Someone like myself for instance, are they able to do the same thing you talk of, only vice versa … towards evolution?

    Do I need a PhD in the geologic sciences, or biology to discern a time discrepancy in Evolution?

  36. #36 BronzeDog
    February 28, 2006

    Rather you have new skeletons, like jurassic beaver, which turn up, and just happen to show that mammals must have been around much earlier, and therefore if they did evolve, the evolution process that Darwin based his theory upon was incorrect, and doesn’t add up.

    Non-sequitur.

    f you believe in : a prehistoric ooze that somehow assembled DNA and the basic genome, if you believe that protozoa turned into fish, accept that fish turned into lizards, and that lizards turned into mammals, and mammals somehow have turned into humans,ALL WITHOUT ANY LINK FROM ONE TO ANOTHER, then you’re smoking crack.

    Good thing we have links.

    Not to mention you would have to explain irreducible complexity. Oh wait you already have explained that.. it was just a big accident, or better yet.. its just rhetoric from liar’s and fools.

    Yup. It’s explained, and IC is just rhetoric from liars and fools. Probably mostly the latter.

    The analogy is clear.

    As mud.

    ID is the tank on the street of baghdad that everyone can see is real, and you are the information minister with his made up stories and BS rhetoric.

    An unfalsifiable, untestable, millenia-old argument from ignorance and lack of imagination is a tank? Comedy at its finest. ID is more like a cardboard cut-out of a tank.

    And jeff keown is the loyal follower, the freedom fighter, the suicide bomber, who goes onto other peoples blogs (like mine) to crusade for his beliefs. It just so happens that I was able to track jeff keown to this site. Thus brininging me to the “terroist training camp”. heheh

    So, now you’re equating debating idiocy to terrorism. I believe that qualifies as the “transfer” technique of propaganda generation.

  37. #37 Antiquated Tory
    February 28, 2006

    Could I maybe, God forbid, have a little more detail from you guys into how C. lutrasimilis impacts our view of early mammals (the cladistics are nice, but..), if you will drag yourselves away from feeding the troll for 5 sec?

  38. #38 Steve
    February 28, 2006

    In response to Mike Janitch, I would agree that when people call you names, it accomplishes little. This simply gives you an excuse to say that they have no answers to your questions. It provides an excuse for you to ignore readily available information.

    In fact, many answers exist, but they’re often not short or simple; even relatively narrowly defined questions can generate book-length responses. And you have to be willing to read these books before you can conclude that there are no answers. You’ve been given some weblinks with specific examples that may begin to answer your questions, so why not start with those? The fossil links that you seek are there, why not read about them?

    You ask “do I need a PhD in the geologic sciences, or biology to discern a time discrepancy in evolution?”.

    Perhaps not a PhD, but I think a little more reading on your part would be helpful. Evolutionary biology is a science that rests on a very broad foundation of knowledge in several different disciplines. Based on your writings on the matter, I have to conclude that there is much that you are unaware of with regards to fossils, specifically, and biology and evolution, in general.

    For example, I think that your concept of “transitional features” (“squirrel half mouse skeleton”) is a bit off, at least to the extent that I can understand what you’re saying here. Evolution predicts that modern squirrel species and modern mouse species shared a common ancestor that was neither “squirrel” or “mouse”, that is, “squirrels” were not at one time “mice”. Why would we expect to find a “hybrid” mouse-squirrel? Why expect to find something that is not predicted by theory? And what does the phrase “”hybrid” skeleton” actually mean, anyway?

    And as for “the fossil proof that a pine cone was once a prehisotric acorn”? Well, we’re not likely to find that either since gymnosperms (conifers, etc.) evolved before angiosperms, including oaks. If your comments reveal a lack of knowledge, don’t be surprises if some of the responses are a tad, um, strong.

    May I gently suggest that you take upper level classes in genetics, developmental biology, geology, vertebrate paleontology and/or human evolution before you take on people that are much better informed. This might enable you to reduce the number of insults that are hurled in your general direction. Scientific debate are not like political debates where success goes to those that are better at playing with words. Success in the a science debate requires a substantial knowledge base. That’s not an insult, it’s just the reality of the game of science.

  39. #39 Jeffery Keown
    March 1, 2006

    Actually, Mike, yours is the first blog I ever did that to, and I wouldn’t have done it except the things you said were so mind-numbingly stupid I just couldn’t help myself.

    Please forgive me, maybe my lack of tolerance is due to some sort of chemical imbalance or (more likely) I’m just a dick.

    Either way, what does it matter? You are still in the dark. There is no “Other Side” to this matter. We have the evidence, the techniques, the facts. What do you have? Incredulity and blathering nonsense.

    Good luck with that.

  40. #40 mike
    March 1, 2006

    Jeff, youre not a dick, you’ve just evolved into one.

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